Gel electrophoresis is a common procedure for the separation of biological molecules, such as DNA, RNA, polypeptides and proteins. In gel electrophoresis, molecules can be separated into bands according to the rate at which an imposed electric field causes them to migrate through a filtering gel. A gel enclosed in a glass tube or sandwiched as a slab between glass or plastic plates can be utilized. Gels have an open molecular network structure, defining pores that are saturated with an electrically conductive buffered solution of a salt. These pores are large enough to enable passage of the migrating macromolecules through the gel.
Polyacrylamide gels are commonly used for electrophoresis. Other gels suitable for electrophoresis include agarose gels and starch gels. Polyacrylamide gel electrophoresis or PAGE is popular because the gels are optically transparent, electrically neutral and can be made with a range of pore sizes. Methods of making PAGE gels are well known. See, for example, B. Hames and D. Rickwood, Gel Electrophoresis of Proteins (2d ed. Oxford University Press, 1990); and A. Andrews, Electrophoresis (2nd ed. Oxford University Press, 1986). In general, stock solutions containing acrylamide monomer, a crosslinker such as bisacrylamide, gel buffers, and modifying agents such as sodium dodecyl sulphate (“SDS”) are prepared. These stock solutions can be stored until a gel is needed. To manufacture a gel, the stock solutions are mixed with water in proportions according to the final desired concentrations of the various constituents. The gel is placed in a chamber in contact with buffer solutions which make electrical contact between the gel and the cathode or anode of an electrical power supply. A sample containing macromolecules and a tracking dye can be placed on top of the gel. An electric potential can be applied to the gel causing the sample macromolecules and tracking dye to migrate toward the bottom of the gel. The electrophoresis is halted just before the tracking dye reaches the end of the gel.
The locations of the bands of separated macromolecules are determined by staining the macromolecules in a sample staining apparatus and then imaging the gel in a separate imaging apparatus. Oftentimes, the image from the imaging apparatus must be manipulated in order to review the results and identify the positions of the various bands. By comparing the distance moved by particular bands in comparison to the tracking dye and macromolecules of known mobility, the mobility of other macromolecules can be determined. Thereby, the size of the macromolecules can then be calculated. Existing methods of electrophoresis require multiple time consuming steps and multiple pieces of large equipment to perform the electrophoresis, the gel staining, the imaging, and the image manipulation/analysis. A need exists in the art for better gel electrophoresis methods, devices, systems, and materials.